Scientists Tried to Reinfect People With Covid – and Failed
Scientists tried to reinfect people with Covid but found it impossible, even when they ramped up the dose 10,000-fold, according to the latest results from the Covid challenge trials. Nature has the details.
When Paul Zimmer-Harwood volunteered to be intentionally infected with SARS-CoV-2, he wasn’t sure what to expect. He was ready for a repeat of his first brush with COVID-19, through a naturally acquired infection that gave him influenza-like symptoms. But he hoped his immunity would help him feel well enough to use the indoor bicycle trainer that he had brought into quarantine.
It turned out that Zimmer-Harwood, a PhD student at University of Oxford, UK, had nothing to worry about. Neither he nor any of the 35 other people who participated in the ‘challenge’ trial actually got COVID-19.
The study’s results, published on May 1st in Lancet Microbe, raise questions about the usefulness of COVID-19 challenge trials for testing vaccines, drugs and other therapeutics. “If you can’t get people infected, then you can’t test those things,” says Tom Peacock, a virologist at Imperial College London. Viral strains used in challenge trials take many months to produce, making it impossible to match emerging circulating variants that can overcome high levels of existing immunity in populations.
Researchers use challenge trials to understand infections and quickly test vaccines and therapies. In March 2021, after months of ethical debate, UK researchers launched the world’s first COVID-19 challenge trial.
The study identified a minuscule dose of the SARS-CoV-2 strain that circulated in the early days of the pandemic that could infect about half of the participants, who had not previously been infected with the virus (at that time, vaccines weren’t yet widely available). [Read the Daily Sceptic write-up of the study here.]
In parallel, a team led by Helen McShane, an infectious-disease researcher at Oxford, launched a second SARS-CoV-2 challenge study in people — including Zimmer-Harwood — who had recovered from naturally caught SARS-CoV-2 infections, caused by a range of variants. The trial later enrolled participants who had also been vaccinated.
The first participants got the same tiny dose of the ‘ancestral’ SARS-CoV-2 strain as did those in the first trial. When nobody developed a sustained infection, the researchers increased the dose by more and more in subsequent groups of participants, until they reached a level 10,000 times the initial dose. A few volunteers developed short-lived infections, but these quickly vanished.
Worth reading in full.
Despite this immunity to the old strains, nearly 40% of the participants reported an Omicron infection after being released from quarantine by December 2022 (and one even reported getting it twice).
The upshot? Natural immunity is extremely robust – even more robust than has previously been suggested – but new variants can appear that evade it with relative ease. We’d kind of figured that out, but it’s good to have it experimentally confirmed.
See more here Daily Sceptic
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Ken Hughes
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This has got to be bullshit, designed to reinforce fear of “variants”.
In my many readings and viewings on the internet with the likes of Sakarit Bahkdi, I understand that immunity relies on recognising many facets of a “virus”, not just one or a few, but many. Any so called variant does not change that much from the previous strain and so is still recognisable by the immune system and dealt with accordingly. Infection usually give immunity for life.
How many people do you know who have had proper flu more than once? I had it at 28 and have never had it since. I am now 76.
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Tom
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I had my worst flu in 1975 (age25) that lasted about 10 days. Since then I rarely get any flu symptoms and they never last more than a day or two. Nothing in the last 20 years.
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Tom
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The virology clown show must go on even though they always have failed to purposely infect anyone with viruses going back to the Spanish Flu (1918).
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Antonio
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Variante di un virus inesistente?
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Anapat
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Esattamente!
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Bob
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It
Doesn’t
Exist
Will
For
Gods
Sake
Ps
It’s really not worth reading in full!
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Bob
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Oh the daily sceptic! Of course
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Wisenox
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There is no such thing as covid. The ‘strains’ are computer models meant to give cover for the vaccine. The vaccines were designed before the covid genome.
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Saeed Qureshi
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“Scientists” LOL!
Ask them which “science” they study and practice. Science only deals with things that exist, i.e., physical samples. As no physical virus sample is available, they cannot inject or work with it. Sorry!
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